Detailed Explanation for this Vulnerability Test
The remote host is affected by the vulnerability described in GLSA-200608-12
(x11vnc: Authentication bypass in included LibVNCServer code)

x11vnc includes vulnerable LibVNCServer code, which fails to properly
validate protocol types effectively letting users decide what protocol
to use, such as "Type 1 - None" (GLSA-200608-05). x11vnc will accept
this security type, even if it is not offered by the server.

Impact

A possible hacker could exploit this vulnerability to gain unauthorized
access with the rights of the user running the VNC server.